Compound engine



(No Model.) 5 Sheets-Sheet l. H. D. DUNBAR.

GOMPOUND ENGINE.

N. FETEns. Pmwmhagnphur. wnsmngmn. n. c.

(No Model.) 5 Sheets-Sheet 2.

H. D. DUNBAR.

T, .ll

(No Model.) 5 sheetssheen 3. H. D. DUNBAR.

' l GOMPOUND ENGINE. No. 276,368. Patented Ap1-.24,1883.

5 R. A B N U D D. H

GOMPOUND ENGINE. No. 276,368. Patented Apr.24,1883.

l (No Model.) 5 sheds-sheen 5.

H.D.VDUNBAR.

QMPOUND ENGINE. N0. 276,368. Patented Apr. 24,1883..

N. PETERS, Phmo-Lnnngmpher. washingw", n. C.

line E of Figs. I and IV.

UNITED STATES PATENT OFFICE.

HENRY D. DUNBAR, OF NORTH HARTLAND, VERMONT.

COMPOUND ENGINE.

SPECIFICATION forming part of Letters Patent No. 276,368, dated April 24, 1883.

Application tiled December 16, 1882. (No model.)

To all whom it may concern Beit known that I, HENRY D. DUNEAE, ot` North Hartland, in the county of Windsor and State of Vermont, have invented a new and useful Improvement in Compound Engines, of which the following is a specification.

The object ot my invention is to provide an economical increase ot' the working power ot' a steam-engine by the use of two cylinders and a steam-chest having' a single steam or valve chamber connected with both cylinders by ports or steam passage-ways, and two pistons secured to a single rod common to both, whereby the piston in one cylinder may be actuated by live steam, andthe piston in the other cylinder may be actuated by theexhaust steam l'rom the first cylinder, or both said pistons may be actuated by live steam; and I accomplish this by the mechanism substantially as hereinafter described, and illustrated in the accompanying drawings, in which- Figure I is a plan view of my invention with the steam-chest case and the valves removed, and showing the arrangement of the cylinders and their connection by steam-passages with the steam chest, and the position ot' the ports in the valve-seat. Fig. II is a vertical longitudinal section ot' my invention at line D ot' Fig. I with the steam-chest case and the valves in position. Fig. III is a vertical longitudinal section of the governing or distributing vaive, valve-seat, and a portion of the casting at Fig. IV is a horizontal section through the steam chest and valves at line H of Fig. II. Fig. Vis a transverse section ofthe small cylinder at line C of Fig. I, showing the manner ot' securing the cylinders Ato the saddle of a locomotive-engine. Fig. VI is a transverse section at line A of Fig. I through the valve-seat of the steam-chest, showing the steam-passage which admits exhaust-steam from the small cylinder to the steamchest, to the governing or distributing valve. Fig. VII is a transverse section at line B of Fig. I, showing the governing or distributing valve and the induction-valve,which controls the passage of steam into and ont of the large cylinder, and the ports and steampassages between said valves, and the connection ofthe steam chest and cylinders with the saddle of a locomotive-engine. Fig. VIII is a plan View ofthe valve-seat, showing the relative position of two of the ports covered by the governing or distributing valve reversed as to their position shown in Fig. I. Fig. IX is aplan view of the valve-seat, showing the chest as arranged for using only exhauststeam in the large cylinder and without any distributing-valve; and Fig. X is a. vertical longitudinal section at line I ot Fig. VIII, showing the governing or distributing valve as used with the relative position ot' the ports S and lI reversed, as shown'in Fig. VIII.

In the drawings, l represents a steam-cylinder having the ordinary casting thereon, which forms the base of the steam-chest, within which are cast the ports or steam-passages, and whose upper side forms the valve-seat upA on which the valves slide in opening' or clos ing the ports.

2 represents another cylinder, smaller in diameter than the cylinderl, and both cylinders are secured or bolted together at the end with their axes coincident, as shown clearly in Fig'. II, and a single piston-rod, 12, extends through an ordinary stniling-box at one end ot' the cylinder1,and through the latter intothe smaller cylinder. I'he adjacent ends ot' these cylinders are each provided with a boss, 40, whose outer ends are snugly tted into and against a tlanged plate, 50,whose tlange holds the cylinders in line with each other, and the cylinder-head on each side of this plateis suitably' packed in any desired manner, as shown in Fig. II. A piston within and fitting each cylinder is secured to the same rod, 12, as shown in Fig. II. When this engine is connected with locomotive it is secured by bolts preferably through tlanges made thereon and through flanges made on the saddle 15. a portion of' which is shown in Figs. V and VII.

3 represents the valve-seat, which is the liottom ot' the chamber within the steanrchest, and in which are made the ports 6, one coinmnnicating with oneend ot' the interior of the cylinder 2 and the other with the other end,

preferably through pipes 6', properly fitted to the castings, although the passage-ways for the steam may be made in the castings, it' desired. An exhaust-port, 7, is made between the ports 6, whose outlet is a port, 8, also made in thevalve-seat,tllese ports 7 and Scommunieating through a passage made in the casting, as shown clearly in FigVI, and also in dotted lines in Fig. I. Ports I are also made in the valve-seat, which communicate, one with the interior of the cylinder 1 at one end andthe other with the other end, as shown clearly in Fig. II, and the exhaust-port 5, made between the ports 41, communicates with the exhaust 5 in the saddle 15, as shown in Fig. VII, and in dotted lines in Figs. I, II, and VI. Forts 9 and 10 are also made in the valve-seat, which communicate with each other by a passage in the casting. as shown clearly in Fi0.VIl, and in dotted lines in Fig. I; and a port, 11, is made between the port S and 9, as shown in Fig. 1, which communicates with the exhaust 5 and exhaust-passage 5 in the saddle, as shown clearly in Fig. III.

The steam-chest is provided with au inlet- Aaperture, as 11, through which the live steam is admitted to the steam-chest, and the ordinary slide-valve, 19, provided with the exhaustcavity 26, controls the opening and closing ot' the ports 6 and 7 t'or the passage of' live steam into and out of the cylinder 2. The ports 4 and 5, and also the port 10, are covered by a single slide induction-valve, 16, having` the usual exhaustcavity,18, and this valve isalso provided with a steam-induction cavity, 17, which extends over and around the exhaustcavity18, with openings therefrom on the lower side of said valve approximately corresponding in size, length, and direction with the ports 4 in the valve-seat, and also with an opening at 1T on the lower side of the valve at one end and beyond the exhaust cavity or recess 1S, as shown clearly in Figs. II, IV, and VII. rIhe two valves 16 and 19 are secured to or connected with a common single valve-rod, 2l, preferably by yokes 22, made on the valve-rod and fitted around each valve, so that each yoke may have a vertical movement on its valve. The valves 16 and 19 are so connected with the valve-rod that when the latter is moved by the ordinary rocker-arm ot'thc engine or locomotive the valve 19 operates in the same manner as any ordinary slide-valve ot' a locomotive, the ends ofthe valve uncovering the ports 6 alternately to admit live steam from the steam-chest through one port 6 into one end of the cylinder 2, and to permit the steam to exhaust from the other end ot' the cylinder out through the other port 6, exhaust recess or arch 20, and exhaust-port 7. As the other valve, 16, is secured to 1the same rod, that valve Vis also moved the same distance as the valve 19; but when said valve 16 is moved to its extreme limit instead of leaving the port 4 exposed and open into the steam-chest, said port then opens into and communicates with the opening in the lower side ofthe valve of the induction-cavity, 17. When the said induction-valve 16 is moved in the opposite direction to its extreme limit the other port 4 opens into and communicates with the other opening ot'the same cavity, 17, at the other end of the valve 16 in its lower side. The governing or distributing valve 24 is also a slide-valve provided with au exhaust recess or arch, 25, and a bridge, as 26, is also made across the valve in the exhaust-recess, with its lower face on the same plane as the lower face of said valve, and of sufficient width to cover the port 11 in the val ve-seat, as shown clearly in Figs. III and IV. This valve 24 is provided with a rod, as 23, which may be secured thereto by a yoke, 30, similar to that hereinbefore described for the other valves, and the said rod 23 extends out through the steam-chest to a point within easy reach et' the engineer, so that said valve21maybemover'i by him into the position as shown in Figs. III and IV with the bridge covering the port 11, or may be moved into the position shown in dotted lines in the same figures with the bridge between the ports 8 and 11. When the said valve is in the latter position the port 9 is lel't exposed and opens into the steam-chest, being uncovered by the valve. rIhe joint where the live-steam passages 14 in the saddle and in the steam-chest unite should be packed in any suitable and convenient manner.

The operation ot' the invention is as l'ollows: Suppose the engine, consisting ot these two cylinders with their pistons and the steam chest and the valves, as above described, to be properly secured in place on each side of an ordinary locomotive, in the place ol'l the ordinary steam chest, valve, and cylinder, and that the valve 21 should be set hy the engineer in the position shown in Fig. IV, and the valve 16 to he moved over to its extreme limit toward the end ot' the chest through which the valve-rod 21 extends. The valve 19 would then be in its corresponding position ot' extreme limit ot' movement, leaving the port 6 at the opposite end of the valve-seat uncovered by the valve 19, and the port t nearest the valve 19 would coincide with the opening 17 in the valve 16. Live steam then admitted into the chest would enter the open port 6 and pass into the end ot the cylinder 2 lfarthest from the large cylinder 1, and force the small piston in a direction toward the large cylinder, and the steam on the opposite side ofthe small piston would pass out through the other port 6 into the cavity 20 in the valve 19, thence into the port 7, and out through the port 8, into the exhaust-cavity 25 of the valve 24; thence down into the port 9, and up through the port 10, into the cavity 17 in the valve 16, passing into said cavity through the opening 17', which extends lengthwise the chestvin the lower face ot' said valve, as shown clearly in Fig. IV, and from said cavity 17 the steam would pass down through the port 4 which coincides with the opening into the cavity 17` and pass into the end of the cylinder 1 nearest the cylinder 2, this exhaust-steam from the cylinder 2 operating to force the piston in the cylinder 1 in the same direction in which the live steam is forcing the piston in the cylinder 2. Of course the two valves 16 and 19 are moved in the opposite direction by the common rod 21, connected with the rocker-arm, as the pistons approach the end of their stroke,

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the same as a single valve is operated in ordinary engines; and when the said valves are so moved in the opposite direction the live steam passes through the other uncovered port 6 intothe opposite end of the cylinder 2, and the exhaust-steam from its other end passes out through the other port 6 and through the same ports and valve 24, and into the cavity 17 of the valve 16, and thence into thel same end of the cylinder 1 corresponding to that ot' the cylinder 2, which contains the live steam. It will thus be seen that when the valve 24 is in the position shown in Fig. IV the live steam from the steam-chest passes into the cylinder 2 to actuate its piston, and the exhaust-steam vtroin the cylinder 2 passes into the cylinder 1 to actuate its piston. Suppose, however, that the engineer moves the valve into a position shown in dotted lines in Figs. III and IV. The steam from the chest will then pass into one end of the cylinder 2 through the uncovered port 6, as before, and the exhauststeam from the other side ot' its piston will pass ont through the other covered port 6 into the exhaust-cavity 2() ot' the valve 19 and down through the port 7 and up through the port 8 into the cavity 25 in the valve 24, thence down through the port 11 into the main eX- haust-passage 5. The live steam from the chest also passes down through the port 9, (left uncovered by the posit-ion ot' the valve 24,) up through the port 1() and opening 17 ot' the valve 16, into thecavity 17, and thence through the port 4which coincides therewith, into that end ot' the cylinder 1 corresponding to the end ot' the cylinder 2, which contains the live steam. In this case the live steam from the chest is admitted to the same side of the pistons in both cylinders, so that both pistons are forced in the same direction by the live steam, so that a much greater forceis brought to bear upon the crank ot' the driving-wheel than is the case when the smaller piston is actuated by live steam and the other by exhaust-steam. Whether t-he live steam is used in one or in both cylinders, the exhaust-steam from the cylinder 1 passes out through the port-1 which is covered at the time by the valve 16, into the lexhaust-cavity 18 in said valve, and'thence down through the exhaust-port 5 and out through the main exhaust 5, as in ordinary engines.

It will be seen that the cavity 17 in valve 16 extends over the exhaust-cavity 1S in said valve, and has` three openings in the lower face of said valve, one on each side ot' and extending iu a direction parallel with the cavity 18 and the other at 17', near one end of the said valve, and extending in a direction at right angles to the length ot' the cavity 1S, and the port 10 being shorter than the opening 17l they always communicate with each other in whatever position the valve 16 may happen to be, so that the cavity 17 in said valve 16 is always ready to take steam from the port 10, whether it be live steam or exhaust, according to the position into which the 24 may have been moved.

As the saddle 15 may be the ordinary saddle of any locomotive which supports the forward part ofthe boiler, and as a single steam-chest having a single chamber is used, it is evident that this engine may be applied to any locomotive already built by removing' the ordinary chest and cylinder and securing this by bolting, as shown in Figs. V and VII. By this system of ports and valves with a steam chest' and two cylinders I am enabled to use a single steam-chest lwith a single steam-chamber and of very much the ordinary form of chest instead ot using two steam-chests each with a steamchamber or a single steam-chest having two separate steam-chambers, as heretofore, and thereby make the engine cheaper, and also better adapted to be secured to a locomotive in place ot the ordinary ones removed. The two adjacent cylinder-heads or the part between the two cylinders may be suitably packed, in any desired manner and with any desired material around the piston-rod, which extends governing-valve through from one cylinder to the other', asv

shown in Fig.`II.

Inasmuch as the valve 16 takes the steam through it into the cylinder 1, Idenominate it the induction-valve 5, andas thecavity 1,7 in the valve16 is to receive the steam which is to be passed into the cylinder to actuate the piston, and theeavity 1S is to receive the steam passing from the cylinder after having been used therein, I denominate the cavity 17 the induction-cavity, and that at 1S the eX- haast-cavity.

I denominate the ports S and 9 in the valveseat induction-ports,7 forthe reason that whatever steam passes through those ports, wheth er live steam or exhaust, is taken into the cylinder to actuate the pistou through the valve 16. In the use ot'a distributing` or governing valve, as 24, made as above described, I have located the bridge, as 26, about midway the length of the valve, to accommodate the position ot'the exhaust-port, as 1l, and these ports 8 and 11 I have located as shown in Figs. I, IV, VI, and VII, in order to save expense and trouble in coring for the casting; but these ports S and 11 mightjust as well be reversed in their relative position to each other, and be located as shown in Fig. VIII, without departing in the least from the principle of operation, in which case the same induction-port, 8, communicates with the exhaust-port 7, and the exhaust-port 11 communicates with the main exhaust-passage as before, and -as shown in dotted lines in Fig. Vlll, in which case the bridge 26 would be made as a tiat part ot' the valve at the end, to cover the port 11, as shown in Fig. X.

In some cases it might be desirable to use the compound engine without the distributing or governing valve 2t; but with the other valves as hereinbet'ore described, in which case the chest and valve-seat would be used IOO IOS

provided with the ports, and the valves 16 and 19, but without the ports S, 9, and 11, and the valve 24; being dispensed with, the induction-port 10 would communicate with the exhaast-port 7, as shown in dotted lines in Fig. 1X, so that live steam would be used in the cylinder 2, which would exhaust through the ports 7 and 10 into and through the inductionvalve 16, into the cylinder 1, in which case exhaust-steam would always be used in one cylinder7 and live steam in the other with no provision for using live steam in both cylinders. It will be seen that as the inductionvalve 16 moves to and fro on its seat the induction-cavity 17 at its movement in one direction is in communication with one induction-port et and at the opposite movement is in communication with the oppositeinductionport 4, and that during its movement in both directions said induction-cavity is in constant and uninterrupted communication with the induction-port 19, to take whatever steam may pass up through the port 10, whether it be live steam or exhaust-steam.

ln the above description I have used the term openings77 as applied to the outlet in the valve-face of the inductioucavity in the valve 16, because this outlet is on three sides ot' the exhaust-recess 1S in said valve; but that outlet is in reality a single continuous opening from the induction-cavity, extending around three sides of' the exhaust-recess 1S,`

that part marked 17 being in constant communication with the port 10, and that part on each side of and parallel with the exhaust-recess 18 being in communication with a port 4 at each alternate movement of the valve.

Having thus described my invention, what I claim as new is '1. 1n an improved compound engine, two cylinders whose axes are coincident, and each containing a piston secured to a rod common to both, a steam-chest whose valve-seatisiprovided with induction-ports 4 and 16 and an exhaust-port, 5, an induction-valve,as 16,whose induction-cavity 17 is adapted to communicate with an alternate induction-port t at each 'ceases movement ot' said valve, and which is in constant communication with the indi'lction-port 10, the induction-ports 6 and exhaust-port 7, covered by an ordinary slide-valve connected to and moved simultaneously with the valve 16 by a rod common to both, the inductionports 8 and 9, and exhaust-port 11, and a distributing-valve, 24, and adapted to be moved independently to open or close said ports, whereby live steam may be admitted to one cylinder and exhaust steam to the other, or live steam is admitted to both cylinders through a single steam-chest, substantially as described.

2. In animproved eompoundengine,a single steam -chest connected with a cylinder, and whose valve-seat is provided with inductionports 4- and 10, communicating with said cylinder, and an exhaust port, 5, an inductionvalve, 16, whose induction-cavity 17 is adapted to communicate with an alternate inductionport 4 at each movement of said valve, and which is in constant communication with the induction-port 19, two induction-ports, 8 and 9, and exhaust-port 1l, and a distributingvalve, 24, adapted to be moved independently A to open or close said ports, whereby live steam or exhaust-steam is received into and conducted through the same chest to the said cylinder to actuate the piston within, substantially as described.

3. A steam -chest whose valve-seat is provided with induction-ports et and 10, and an exhaust-port, 5, an induction-valve, 16, always covering said ports, and provided with an haust-cavity, 1S, and a'n induction-cavity, 17, having an opening in the valve-face on three sides of said exhaust-cavity, whereby said induction-cavity may be in communication alternately with each induction-port 4, and be in constant communication with the inductionport 10, substantially as described.

HENRY D. DUNBAP.

Witnesses:

C. A. Gnarls, Unas. H. Woon. 

